Abraham Lincoln said, “Character is like a tree and reputation like its shadow. The shadow is what we think of it; the tree is the real thing.” Sen. John McCain, R-Ariz., was the real thing, and that is why his reputation will cast such a long shadow over our politics for years to come. McCain was the rare celebrity who was even more impressive in person than on television. I first met him after the publication of my 2002 book, “The Savage Wars of Peace: Small Wars and the Rise of American Power.” An avid student of history, McCain read the book and liked it, especially because, unbeknownst to me, it featured one of his ancestors – an army officer who had fought the Mexican revolutionary Pancho Villa in 1916. His love of literature was not for show. I remember on a flight to the Munich Security Conference wandering to the front of the Air Force executive jet to find McCain engrossed in a lengthy historical tome. Imagine that – a politician who spent his spare time reading history. Or anything at all.